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minikube on portabledevops

minikube is the solution for single node kubernetes cluster inside a VM.

portabledevops is portable devops tool set on windows, I used msys64 as demo on win7 here.

minikube features

  • DNS
  • NodePorts
  • ConfigMaps and Secrets
  • Dashboards
  • Container Runtime: Docker, and rkt
  • Enabling CNI (Container Network Interface)
  • Ingress

kubernetes concept

master

  • coordinates all activities in your cluster
  • scheduling applications
  • maintaining applications’ desired state
  • scaling applications
  • rolling out new updates

pod

  • basic building block of Kubernetes
  • represents a running process on your cluster
  • a Kubernetes abstraction that represents a group of one or more application containers
  • Shared storage, as Volumes
  • Networking, as a unique cluster IP address, each container in a Pod shares the network namespace, including the IP address and network ports
  • Information about how to run each container, such as the container image version or specific ports to use

node

  • a node is worker machine, can be vm or physical
  • a pod always run on a node
  • a node can have multi pods
  • master to handle scheduling
  • kubelet is a process for communication between kubernetes master and nodes, managing pods and containers

service

  • abstraction which defines a logical set of Pods and a policy by which to access them
  • enable a loose coupling between dependent Pods
  • defained using YAML (preferred) or JSON
  • determined by a LabelSelector
  • each Pod has a unique IP address, those IPs are not exposed outside the cluster without a Service

volume

  • simply a directory on disk or in another container
  • has an explicit lifetime – the same as the pod that encloses it

namespaces

  • provide a scope for names
  • divide cluster resources between multiple users

deployment

Deployment creates pods with containers inside them, not creating containers directly.

minikube download

This test is on win7 so download latest 64bit binary from link

place to win7, for me is here:

$ which -a minikube
/C/oldhorse/portableapps/dockertoolbox/minikube

minikube installation

Let’s start minikube, it create/start a VM in Virtualbox name as minikube:

  • memory 2GB
  • CPU 2
  • disk 20GB
$ minikube version
minikube version: v0.22.2

$ minikube start
There is a newer version of minikube available (v0.24.1).
Download it here:
https://github.com/kubernetes/minikube/releases/tag/v0.24.1
To disable this notification, run the following:
minikube config set WantUpdateNotification false
Starting local Kubernetes v1.7.5 cluster...
Starting VM...
Getting VM IP address...
Moving files into cluster...
Setting up certs...
Connecting to cluster...
Setting up kubeconfig...
Starting cluster components...
Kubectl is now configured to use the cluster.

minikube upgrade

From last session there is latest v0.24.1 64bit binary available, download it from link

replace here,
/C/oldhorse/portableapps/dockertoolbox/minikube

Have a try new version of minikube:

$ minikube start
Starting local Kubernetes v1.8.0 cluster...
Starting VM...
E1209 12:10:07.451560 13164 start.go:150] Error starting host: Temporary Error: Error configuring auth on host: ssh command error:
command : sudo systemctl -f restart crio
err : Process exited with status 5
output : Failed to restart crio.service: Unit crio.service not found.

Not sure the reason behind of those error, would be better to remove cluster and re-create it using new minikube.

$ minikube status
minikube:Running
cluster:stopped
kubectl: Correctly Configured: pointing to minikube-vm at 192.168.99.100

$ minikube delete
Deleting local Kubernetes cluster...
Machine deleted.

It looks good this time,

$ minikube version
minikube version: v0.24.1

$ minikube start
Starting local Kubernetes v1.8.0 cluster...
Starting VM...
Downloading Minikube ISO
140.01 MB / 140.01 MB [============================================] 100.00% 0s
Getting VM IP address...
Moving files into cluster...
Downloading localkube binary
148.25 MB / 148.25 MB [============================================] 100.00% 0s
0 B / 65 B [----------------------------------------------------------] 0.00%
65 B / 65 B [======================================================] 100.00% 0sSetting up certs...
Connecting to cluster...
Setting up kubeconfig...
Starting cluster components...
Kubectl is now configured to use the cluster.
Loading cached images from config file.

$ minikube status
minikube: Running
cluster: Running
kubectl: Correctly Configured: pointing to minikube-vm at 192.168.99.101

I comment on this existing issue of minikube here

ssh to minikube vm

$ minikube ssh
_ _
_ _ ( ) ( )
___ ___ (_) ___ (_)| |/') _ _ | |_ __
/' _  _ \| |/' _ \| || , < ( ) ( )| '_\ /'__`\
| ( ) ( ) || || ( ) || || |\`\ | (_) || |_) )( ___/
(_) (_) (_)(_)(_) (_)(_)(_) (_)\___/'(_,__/'\____)

$ hostname
minikube
$ df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 933M 0 933M 0% /dev
tmpfs 1001M 0 1001M 0% /dev/shm
tmpfs 1001M 8.8M 992M 1% /run
tmpfs 1001M 0 1001M 0% /sys/fs/cgroup
/dev/sda1 17G 831M 15G 6% /mnt/sda1
/c/Users 440G 240G 201G 55% /c/Users
$

will see minikube service running as docker containers in vm,

$ which -a docker
/bin/docker
/usr/bin/docker
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS
NAMES
eba767c6b6be gcr.io/google_containers/echoserver "nginx -g 'daemon ..." 12 minutes ago Up 12 minutes
k8s_hello-minikube_hello-minikube-57889c865c-zcfcn_default_80f0ba0a-dd07-11e7-bd7f-0800271d37e3_0
b608a9cee6f8 gcr.io/google_containers/pause-amd64:3.0 "/pause" 12 minutes ago Up 12 minutes

$ docker inspect eba767c6b6be

reusing docker daemon on host

Above session we demoed how to run and check docker inside minikube vm via ssh, in fact you can reuse local host docker toolset.

First need to export all env to local host, for me it is win7 msys64, it is same position as OSX.

$ minikube docker-env
export DOCKER_TLS_VERIFY="1"
export DOCKER_HOST="tcp://192.168.99.101:2376"
export DOCKER_CERT_PATH="C:\oldhorse\portableapps\msys64\home\username\.minikube\certs"
export DOCKER_API_VERSION="1.23"
# Run this command to configure your shell:
# eval $(minikube docker-env)

This is just verify not export yet, so need to execute all above by:

$ eval $(minikube docker-env)

then run local docker will give running containers, which same as inside minikube vm,

$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS
NAMES
eba767c6b6be gcr.io/google_containers/echoserver "nginx -g 'daemon ..." 19 minutes ago Up 19 minutes
k8s_hello-minikube_hello-minikube-57889c865c-zcfcn_default_80f0ba0a-dd07-11e7-bd7f-0800271d37e3_0
b608a9cee6f8 gcr.io/google_containers/pause-amd64:3.0 "/pause" 19 minutes ago Up 19 minutes
cut

minikube dashboard

it is web based dashboard,

$ minikube dashboard
Opening kubernetes dashboard in default browser...

it launch web browser at url:
http://192.168.99.101:30000/#!/node?namespace=default

persistent volumes

default persist files stored these folders:

  • /data
  • /var/lib/localkube
  • /var/lib/docker 
    $ df -h /data
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 17G 831M 15G 6% /data
$ df -h /var/lib/localkube
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 17G 831M 15G 6% /var/lib/localkube
$ df -h /var/lib/docker
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 17G 831M 15G 6% /var/lib/docker

mounted host folders

this is default shared folder via Virtulbox,

/c/Users 440G 240G 201G 55% /c/Users

it can be used for file transfer between local host and minikube vm.

kubectl

  • kubectl a command line interface for running commands against Kubernetes clusters
  • deploy and manage applications on Kubernetes
  • inspect cluster resources
  • create, delete, and update components

kubectl installation

You can download latest win x86 64bit binary,

curl -LO https://storage.googleapis.com/kubernetes-release/release/v1.8.0/bin/windows/amd64/kubectl.exe

then add binary to your PATH or place to portable path like me,

$ curl -LO https://storage.googleapis.com/kubernetes-release/release/v1.8.0/bin/windows/amd64/kubectl.exe
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 50.2M 100 50.2M 0 0 4716k 0 0:00:10 0:00:10 --:--:-- 5039k

$ which kubectl
/C/oldhorse/portableapps/dockertoolbox/kubectl
$ cp kubectl.exe /C/oldhorse/portableapps/dockertoolbox/
$ kubectl version
Client Version: version.Info{Major:"1", Minor:"8", GitVersion:"v1.8.0"

kubectl commands

kubectl get nodes
kubectl get pods
kubectl get services
kubectl get deployments